MEASUREMENT OF ORIENTATIONAL RELAXATION-TIMES OF OH IN A FLAME USING PICOSECOND TIME-RESOLVED POLARIZATION SPECTROSCOPY

被引：24

作者：

DREIZLER, A ^{[1
]}

TADDAY, R ^{[1
]}

SUVERNEV, AA ^{[1
]}

HIMMELHAUS, M ^{[1
]}

DREIER, T ^{[1
]}

FOGGI, P ^{[1
]}

机构：

[1] UNIV FLORENCE,EUROPEAN LAB NONLINEAR SPECT,I-50125 FLORENCE,ITALY

来源：

CHEMICAL PHYSICS LETTERS | 1995年 / 240卷 / 04期

关键词：

D O I：

10.1016/0009-2614(95)00472-G

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Picosecond time-resolved polarization spectroscopy in the ultraviolet has been used to measure relaxation times of the laser-induced optical anisotropy of OH in an atmospheric pressure name. OH radicals were produced in the post flame gases of a methane/air flame. Transient signals from absorption in the A(2) Sigma-X(2) Pi (0-0) electronic transition were studied by pump-probe experiments using different P-and Q-branch transitions. A theoretical approach has been developed to interpret experimentally observed transient signals in terms of the relaxations of molecular orientation and alignment. The observed effective relaxation times for these flame conditions are of the order of 240-590 ps depending on the rotational state. We found slightly larger values for the relaxation times of molecular orientation than for molecular alignment. These results are relevant to the interpretation and modeling of four-wave mixing spectra.

引用

页码：315 / 323

页数：9

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